Method for the quantitative determination of soldering agent residues

Abstract

A method for quantitatively determining flux material residues remaining on a heat exchanger after a preceding soldering process is provided. To this end, a fluid is applied to the heat exchanger, wherein the remaining quantity of flux material on the heat exchanger after the preceding soldering process is derived from the concentration of soldering agent in the fluid.

Description

[0001]This nonprovisional application is a continuation of International Application No. PCT / EP2010 / 068096, which was filed on Nov. 24, 2010, and which claims priority to German Patent Application No. DE 10 2009 055 610.9, which was filed in Germany on Nov. 25, 2009, and which are both herein incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The invention relates to a method for the quantitative determination of soldering aid residues, which remain on a workpiece after a preceding processing step, in which the workpiece is acted upon by a fluid. Further, the invention relates to an apparatus which is suitable to a particular degree for carrying out the method. Moreover, the invention relates to a method for dimensioning a workpiece and / or another part.[0004]2. Description of the Background Art[0005]During the processing of workpieces, it is typical in certain processing steps and often also necessary that they be treated with an auxiliary mate...

AI Technical Summary

Benefits of technology

[0019]It is proposed, further, to carry out the method in such a way that at least at times, preferably at least initially, it is carried out under defined conditions, particularly with respect to the workpiece temperature, the fluid temperature, the duration of the measuring process, the fluid throughput through the workpiece, the composition of the fluid, the pressure, and / or the duration of the measurement. When using conditions defined in such a way, it is especially possible to be able to obtain especially meaningful and reproducible measurement results. In initial tests, it became apparent, moreover, that particularly the mentioned parameters have an especially great effect on the significance of the obtained measured values.

[0020]It is proposed, further, to carry out the method in such a way that at least at times and / or at least partially it is carried out as a circulation process. In particular, this can be a closed circulation process. It is possible in this way to determine the remaining soldering aid amount especially well, particularly largely completely, without an excessive amount of fluid being necessary. Moreover, the measuring accuracy of the method can improve, because a relatively high concentration value in the fluid is ultimately measured, which typically results in lower measuring accuracies. Moreover, the consumption of fluid can be reduced and, for example, the energy necessary for carrying out the method (particularly heat energy for the fluid) can be reduced, which is also an advantage.

Problems solved by technology

Typically, the use of flux materials also entails flux material residues on the workpiece and thereby the associated disadvantages.

In particular, after the workpiece is finished, soldering agent residues remaining on it can impair the function and durability of other components, working together with the soldered workpiece, and possibly also the workpiece itself, for example, by corrosion.

In fact, it is basically possible to remove soldering agent residues from the workpiece after the soldering process has been completed (for example, by washing), but this can prove to be costly and complicated, particularly when the subsequently necessitated drying processes for the workpiece are considered in addition.

Reduction of the amount of the used flux material is also not easily possible, because such a decrease in the flux material amount can entail a worsening of the soldering result, which is likewise undesirable.

The aforementioned problems arise especially to a particular degree when it concerns the processing of workpieces that have especially fine structures and / or especially many curved surfaces (particularly also with small radii of curvature) and in part closed hollow spaces.

Because of the varied hollows spaces in such heat exchangers, washing of the heat exchanger after soldering proves to be tedious and problematic.

A reduction in the amount of employed flux material is also out of the question, because due to the large proportion of parts to be soldered together the risk of leaking would rise very rapidly to no longer acceptable values.

Another problem occurring in practice is that with the use of soldering aids, particularly of flux materials, empirical values are often drawn upon, when it is a matter of determining the amount of soldering aids to be used during the processing of the workpiece.

Because resoldering of workpieces is relatively complicated and expensive, the tendency therefore is to select the amount of the employed soldering aid as higher than the actually necessary amount (this also applies to scrap workpieces).

This leads not only to an unnecessarily high consumption of soldering aids (which entails corresponding production costs and environmental pollution unnecessary per se), but also to the situation that the workpiece and other parts, operated together with the workpiece, in a machine are exposed to correspondingly higher wear by the (unnecessarily) high soldering aid residues, and accordingly must be constructed as more durable.

This also leads to disadvantages such as particularly cost and weight disadvantages.

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